In methods, which are common in practice, for folding an edge with and without an edge of another sheet metal component to be clamped in the fold, the bent edge is folded in several stages by means of a folding roller whose outer surface is cylindrical. Even in the case of this multiple-stage folding, a material bulge in advance of the folding roller develops at higher operational speeds, which then leads to a critical speed being exceeded whereupon the folding roller skips over the material bulge which leads to folding errors. As a result, the operational speed of the folding roller, depending upon the thickness of the sheet metal to be folded, is limited to 200 mm/s.
A method for folding an edge of a sheet metal component of the type mentioned in the introduction is known (EP 1 445 043 A1, FIGS. 4 and 5 of the associated text). In this method, the axis of rotation of the conically contoured roller is only inclined with respect to the plane of the sheet metal component to be folded. This produces a comparatively short section of the folding process in the movement direction of the roller. As a result, considerable deformation forces are required and there is a risk of producing a suboptimum folding result.